Cryptology ePrint Archive: Report 2009/500

Key Recovery Attack on QuiSci

Nils Reimers

Abstract: This paper shows a key recovery attack on QuiSci (quick stream cipher), designed by Stefan Müller (FGAN-FHR, a German research institute) in 2001. With one or few know plaintexts it's possible to recover most of the key with negligible time complexity.
This paper shows a way how to exploit the weak key setup of QuiSci.